Numbers beginning with 202-453

Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. The signing of the Residence Act on July 16, 1790, approved the creation of a capital district located along the Potomac River on the country's East Coast. As permitted by the U.S. Constitution, the District is under the exclusive jurisdiction of the Congress and is therefore not a part of any U.S. state. source

202 is the North American telephone area code for Washington, D.C. It was one of the area codes originally assigned in October 1947. The capital was assigned 202 because the North American Numbering Plan Administration wanted to keep the number of "clicks" to a minimum for densely populated areas, given the rotary dialing technology in use at the time. Though area codes as short as 5 clicks were possible for area codes covering just a city or portion of a state, area codes covering an entire state always had 0 as the middle digit. The District was treated the same as a state by NANPA, and was thus assigned an area code with 14 clicks, tied with Maryland's 301 as the second-fastest single-state area code that could be dialed under NANPA's original guidelines (0 and 1 were not allowed as the first digit, the second digit was either 0 or 1, and the third digit could not be the same as the second digit). The only faster one was New Jersey's 201. source